1. Field of the Invention
The present invention relates to improved battery cell charging and cycling devices.
The term "cycling device" designates in the present specification a device which conditions battery cells by at least sequentially discharging and charging the same.
2. Brief Description of the Prior Art
U.S. Pat. No. 4,342,954 (GRIFFITH) issued on Aug. 3, 1982 describes a battery conditioning apparatus comprising a first electronic circuit which causes serially interconnected battery cells to supply a discharge current until the voltage across these cells reaches a predetermined lower limit. Such a discharge mode of the battery conditioning apparatus is indicated through a first light-emitting diode (LED).
After the voltage across the battery cells to be conditioned has reached the predetermined lower limit, a second electronic circuit supplies a constant charging current to the battery cells during a predetermined period of time. Such a charge mode of the conditioning apparatus is indicated through a second LED.
A first disadvantage of the battery conditioning apparatus of U.S. Pat. No. 4,342,954 is that it is only designed for use with a specific type of battery cells. More particularly, the conditioning apparatus does not provide for adjustment of the discharge and charging currents in relation to the type of battery cell to be conditioned. Even if the charging current can be varied through a potentiometer, each adjustment of the amplitude of the charging current requires accurate measurement of the latter current.
Another drawback of the battery conditioning apparatus of U.S. Pat. No. 4,342,954 is that the first and second LED's can indicate the discharge and charge modes even if the discharge and charging currents are interrupted and the timing circuit determining the time of charge of the battery cells is malfunctioning.